System Components

PASS-Key II(R) System Components (Typical):

Ignition Key Assembly

The ignition key assembly for vehicles equipped with the PASS-Key II system is an assembly of a typical square ignition key blank and resistor assembly. The ignition key blank and resistor assembly are not serviceable separately. There are 15 different ignition key assemblies,each with a different resistance value. The ignition key assembly also has mechanical cuts similar to non-PASS-Key II ignition key assemblies.

Important
^ When servicing the PASS-Key II system, obtain all ignition key assemblies, if possible, and verify proper values with tool J 35628-A, VATS/PASS Interrogator.

Steering Column Lock and Ignition Cylinder Assembly

Ignition Cylinder Assembly Wire Routing:

The ignition cylinder assembly in vehicles equipped with the PASS-Key II system contains a set of electrical contacts used to measure the resistor assembly in the ignition key assembly. When servicing the ignition cylinder assembly, be certain to maintain proper wire routing. A two pin connector at the base of the steering column assembly connects the contacts to the vehicle wiring. The connector is also used for diagnostic purposes. The ignition cylinder assembly also performs all functions of Ignition cylinder assemblies on non-PASS-Key II vehicles. When replacing an ignition cylinder assembly, it will be necessary to make new ignition key assemblies which match the PASS-Key II key code of the theft deterrent module assembly and the mechanical cut of the new ignition cylinder assembly.

Important
^ The wire routing for the contacts inside the steering column assembly is critical.

Theft Deterrent Module Assembly

The theft deterrent module assembly contains the logic of the PASS-Key II system. The theft deterrent module assembly has inputs from the ignition circuit and the resistor assembly. The theft deterrent module assembly has outputs to the starter enable circuit, the fuel enable circuit, and the security lamp circuit.

Ignition Input

The ignition input is used to turn the theft deterrent module assembly on. When the theft deterrent module assembly is turned on, it will read the resistor assembly and control the outputs accordingly. When the theft deterrent module assembly is turned off the resistor assembly is not read, and the theft deterrent relay assembly and fuel enable output will not allow the engine to start. When the ignition switch is in the "OFF" position, the Battery input to the theft deterrent module assembly will draw about 1 milli-amp.

Key Resistor Inputs

The key resistor inputs are used to determine if the correct ignition key assembly is being used to start the vehicle. The key resistor inputs are read only when the theft deterrent module assembly is first turned on. If the key code (resistance value) of the ignition key assembly matches the value stored in the theft deterrent module assembly, the theft deterrent relay assembly and fuel enable output will allow the vehicle to start. If the resistance value of the ignition key assembly does not match the value stored in the theft deterrent module assembly, the relay assembly and fuel enable output will not allow the vehicle to start.

Starter Enable Output

The starter enable circuit controls the theft deterrent relay assembly. When the theft deterrent module assembly sees the proper resistance at the ignition key assembly, it grounds the starter enable circuit which allows the engine to be cranked. If the theft deterrent module assembly does not see the proper resistance at the ignition key assembly, it will not ground the starter enable circuit.

Fuel Enable Output

The fuel enable circuit is an output from the theft deterrent module assembly and an input to the PCM. When the theft deterrent module assembly sees the proper resistance at the ignition key assembly, it will output a pulse width modulated (PWM) signal to the PCM. If the theft deterrent module assembly does not see the proper resistance at the ignition key assembly, it will not output the PWM signal to the PCM.

Security Indicator Lamp Output

The "SECURITY" lamp circuit is an indicator lamp output. The lamp output will be grounded during a five second "bulb test" at key on, at any time that the theft deterrent module assembly is preventing the engine from starting, or if the theft deterrent module assembly is not properly programmed.

Theft Deterrent Relay Assembly

The relay assembly is used to stop the engine from cranking if the correct resistance is not sensed at the ignition key assembly. It prevents the engine from cranking by opening the circuit to the starter solenoid switch.

Powertrain Control Module (PCM)

The PCM reads the fuel enable circuit to determine if fuel injection should be allowed. If the fuel enable signal is not present, the PCM will not allow fuel injection. If the signal is present, the PCM will allow fuel injection and normal engine operation.

The PCM has some diagnostic features associated with the fuel enable input, including diagnostic trouble codes.